The human brain is sensitive to light

The human brain is sensitive to light, breakthrough findings from Valkee and the University of Oulu

August 11, 2011. Helsinki, Finland and Bergen, Norway – Valkee, inventor of the world’s first bright-light headset, and scientists from the University of Oulu will present new findings on human brain’s photosensitivity at the Scandinavian
Physiology Society Annual Meeting 2011, August 12-14.
 
Their research localized the OPN3 protein  – known as the  light-sensitive photoreceptor protein  – in all of the 18 evaluated areas of the brain. These brain areas include the core areas of serotonin and melatonin production and storage, which play key roles in mood, sleep and depression.  The study shows that the human brain is sensitive to light also outside of the visual system.

“The human brain is broadly photosensitive. The  photoreceptor  proteins we found are known to take light stimulus and transfer it into neural signals.  Channeling light directly to these brain  areas via ear canal  will  generate  a response in the photosensitive cells”, commented Juuso Nissilä, Valkee co-founder and chief scientific officer.

“The study shows that we have brain cells that react to light when exposed directly. These results are encouraging, especially for bright-light therapy channeled via ear canal direct to brain tissue”, summarized professor Seppo Saarela, PhD, head of  the
biology department and leading the research at the University of Oulu.

Valkee launched its bright-light  headset in August 2010. Being based on crossfunctional science in neurology, biology and psychiatry, Valkee is a CE-certified Class II(a) medical device under the EU regulations.

About Valkee
The Valkee bright-light headset channels bright light direct to the human brain via ear canals to prevent and cure mood swings and circadian-rhythm disorders such as jetlag. In clinical trials, 9 of 10 patients suffering from severe seasonal affective
disorder – also known as winter blues – experienced total symptom relief in 4 weeks with a daily 8-12 minute dose. Valkee is based on scientific studies carried out since 2007 and is a CE-marked Class II(a) medical device.

About the presented research
Method: The distribution and localization of OPN3 protein in human brain and peripheral tissues was assessed by immunohistochemical staining, using polyclonal antibody against OPN3.  The  OPN3 protein content was  measured using western blotting  and SDS-PAGE. The samples from nine cadavers were assessed during forensic examination. Samples were cut into sections and fluerescent dye labeled antibody was used to stain before confocal laser scanning microscopy. Primary
antibody omitting and immunizing peptide blocking experiments secured the specificity of labeling and immununoreaction.
Results: The OPN3 protein is abundant in the human brain and, as expected, not in periphery or in negative controls. Neuronal OPN3 was present in granular pattern intracellularly in all of the  eighteen examined sites, including numerous cerebral
cortical areas,  cerebellar cortex and several nuclei in phylogenetically old regions.

Immunoreaction took place mostly in neuronal soma, but not in nuclei. Conclusion: Previously in mRNA-level assessments,  OPN3 encoding  has  actually resulted in the abundant presence of OPN3 protein in neurons of human brain, but not in non-neuronal peripheral tissues. OPN3 (aka. panopsin or enkephalopsin) belongs to the families of extraretinal opsins which have putative role in CNS tissue photosensitivity. OPN3 mRNA has previously been localized in rodent brains and in mRNA expression level in the human brain, but the actual protein and it’s location has not been clarified. In this study, we aimed to define OPN3 protein localization, its abundance in the human brain and the site of cellular locality